feat: extract FilterEngine IIFE module from JavaScript.html (Phase 1 PR4/7)

[cheerc]

What

Extract 8 filter methods from JavaScript.html into a new FilterEngine.js.html IIFE module as part of Phase 1 IIFE domain separation (#129).

Methods Extracted (8)

Method	Type	Notes
loadAndApplyPersistedFilters	public	UI callback heavy, this → App
toggleAllFilterCheckboxes	public	DOM querySelectorAll
applyFilters	public	Advanced filter apply
clearAdvancedFilters	public	Clear non-tag filters
clearAllFilters	public	Clear all filter state + localStorage
_filterScheduleData	private	Core predicate-based data filter
filterDataByTags	public	Tag filter pipeline
filterDataByActiveFilters	public	Multi-type filter pipeline

Not extracted: applyTagFilters (async, Tagify instance + modal confirm — stays in JavaScript.html as documented in NOT_EXTRACTABLE).

How

• Created FilterEngine.js.html with standard IIFE pattern (function(App) { ... })(App)
• Converted all this.xxx → App.xxx references (activeFilters, ui, modals, tagFilterTagify)
• Added include in Index.html after DataCollection.js (provides App.getAllTags), before App.init()
• Updated IIFE_EXTRACTED set in appWiringContracts.test.js (+8 methods)
• Updated syncMethodsWiring.test.js: added filterEngineSource, updated method existence checks and wiring patterns (this\.xxx → App\.xxx)
• Moved _filterScheduleData from PRIVATE_HELPERS to IIFE_EXTRACTED
• Updated public method count: 26 → 19

Scope

• FilterEngine.js.html (new)
• JavaScript.html (removed 8 methods, added moved comments)
• Index.html (+1 include line)
• tests/unit/appWiringContracts.test.js (IIFE_EXTRACTED, counts)
• tests/unit/syncMethodsWiring.test.js (source file, patterns)

Verification

• npm test: 1147 tests passed (36 files)
• npx eslint --ext .html .: 0 errors (8 pre-existing warnings)
• bash scripts/check-structure.sh: all present
• Scope gate: only expected 5 files changed

ESLint Baseline (unchanged)

8 warnings (all pre-existing: unused vars in Config, Elements, module factories)

refs #129

[cheerc]

✅ VERIFIED

Reviewed HEAD: 3f56068eb9fc5abf68644b989d9dcc473dfb4013
Reviewer: cb-team-reviewer
Audit mode: standard (D2 — Risk-Flag #2 touched but extraction is mechanical)

Files Reviewed (5)

• FilterEngine.js.html (new, +141) — IIFE module with 8 extracted filter methods
• JavaScript.html (-118) — removed 8 methods, left move comments
• Index.html (+1) — include line for FilterEngine.js
• tests/unit/appWiringContracts.test.js (+9/-8) — IIFE_EXTRACTED set, counts
• tests/unit/syncMethodsWiring.test.js (+34/-14) — source, patterns, existence checks

Stage 1 — Correctness

• All 8 methods (7 public + _filterScheduleData) correctly extracted with this → App conversion (43 App. references, 0 residual this.)
• IIFE pattern (function(App) { ... })(App) consistent with PR1-PR3
• Load order: Elements → JavaScript → DataCollection → FilterEngine → App.init() ✓
• AppElements (global const) accessed directly — same pattern as original code
• applyTagFilters (async, Tagify-dependent) correctly NOT extracted, remains in JavaScript.html
• Caller sites in JavaScript.html (this.loadAndApplyPersistedFilters() at L213, L387) work correctly via this === App context
• No cross-module callers in UtilityFunctions/LockManager/DataCollection
• Test counts: 48 - 7(PR1) - 4(PR2) - 11(PR3) - 7(PR4) = 19 public methods ✓
• PRIVATE_HELPERS correctly emptied, _filterScheduleData moved to IIFE_EXTRACTED
• syncMethodsWiring: this\\. → App\\. patterns for clearAdvancedFilters, clearAllFilters ✓
• No conflict markers in any file

Stage 2 — Adversarial

• No hidden this context bugs — all this.xxx → App.xxx conversions verified line-by-line
• No missing dependency: App.getAllTags (DataCollection) loads before FilterEngine
• AppElements global scope: defined in Elements.js.html (L469), loads before FilterEngine (L479)
• No scope leak: IIFE wraps everything, only App.xxx = assignments escape

Evidence

• ran: gh pr checks 148 → validate: SUCCESS
• ran: grep this\. FilterEngine.js.html → No this. references found
• ran: conflict marker scan (5 files) → all clean
• cited: FilterEngine.js.html:16 — (function(App) { (IIFE entry)
• cited: FilterEngine.js.html:141 — })(App); (IIFE closure)
• cited: Index.html:479 — FilterEngine.js after DataCollection.js
• cited: appWiringContracts.test.js:134 — expect(publicMethods.length).toBe(19) (count verification)